This will be sure prohibited. Only possible if your model will got level 3 autopilot, which now have only few models on market (Tesla's only have level 2 officially).
These lights meaning, MANUFACTURER will be responsible in case of any issues, caused by autonomous driving vehicle.
Well they could, but retrofit your Honda Jazz all you want, you will be getting pulled over if you're watching a movie on the tablet you're hanging from the windshield.
On an obviously old car, correct, but on newer looking cars, it might not be worth the hassle to pull them over. Unless there is a way of tying it to the license plate that the police cameras scan, it’s soon going to make it hard to make sure each officer is aware of the specific models. Which means some officers will probably choose to ignore anything with these lights and some may choose to pull over vehicles even with clearance.